Bosch LBB 1925-10 User Manual

Communications Systems | LBB 1925/10 Plena System Pre-Amplifier

LBB 1925/10 Plena System Pre-Amplifier

www.boschsecurity.com

u Six-zone system pre-amplifier, with single or dual

channel operation

u Two input channels for call stations

u Universal input for microphone/line, with speech

optimized tone control

u Three inputs for BGM selection and music optimized

tone control

u Front panel zone selection for BGM and call station

zone selection for calls

The Plena system pre-amplifier is a versatile, high­performance unit with call and mono BGM
(background music). It fulfills a wide variety of public
address requirements at a surprisingly low cost. It can
provide dual channel operation for simultaneous calls
and BGM for up to six different zones, using two Plena
amplifiers.

Functions

The call channel provides two inputs for the Plena call
stations, LBB 1941/00 (all-call) or LBB 1946/00 (six­zone), with loop-through capability, and universal,
balanced input. One is a 3-pin XLR connector for
microphone or line level (selectable), and the other is
a 5-pin DIN-connector with all‑call priority contact,
which may also be used to start one of the available
chime attention signals.

The microphone input has a selectable speech filter
for improved intelligibility, a volume control, and bass
and treble tone controls with shelving characteristics
optimized for speech. The call channel is available on
the balanced XLR master output.

The BGM channel provides three inputs on stereo
cinch-connectors, converted to mono, with front panel
selection, volume control and bass and treble tone
controls with shelving characteristics optimized for
music. The BGM channel has a direct output on
balanced XLR for dual channel operation. It can also
feed the master output, with the lowest priority, for
single channel operation. Zone selector switches on
the front panel control the BGM routing. An overload
protected 24 VDC output provides power for driving
external relays, often making an external power supply
unnecessary.

An emergency/telephone input with signal level
detector (VOX) and volume preset has the highest
priority to all zones. Two trigger inputs (contact
closure) activate alarm or time signals to pre-selected
zones. Many different chime tones are available. A PC
audio input with RS-232 control provides software
controlled zone configuration, or automatic messaging
in combination with the LBB 1965/00 Plena Message
Manager. There are six levels of priority available for
BGM, microphone, call stations, trigger inputs and
emergency input. A set of relays directs the amplifier
output(s) to different loudspeaker groups (zone
switching).

2 | LBB 1925/10 Plena System Pre-Amplifier

Each zone has a tri-state control on the front panel
that can turn it off, switch it to the call channel, or to
the BGM channel. The all‑call microphone input and
emergency activation override the call station
selection on the call channel. Each zone has separate
priority overrides with preset volume levels. This
assures an appropriate message volume, independent
of any local volume settings, such as for BGM. Both
three‑wire and four‑wire override schemes are
supported. An override also activates a voltage-free
contact (call-active) available for external control and
monitoring. The master output channel, or one of the
input channels, can be monitored through the
headphone connector and/or the LED VU‑meter.

Controls and indicators

Front

• LED power meter

• Power on LED

• Call active LED

• Three knobs for mic/line volume, treble, and bass
levels

• Three knobs for BGM volume, treble, and bass levels

• BGM source selection knob

• Six zone-selections keys

• Six zone status LEDs

• On/off switch

Back

• EMG input volume control

• Mains voltage switch

Interconnections

Front

• Headphone jack

Back

• One (DIN or XLR) Mic/line input

• Two (DIN/DIN) call station inputs

• PC audio (cinch) input

• Priority input

• Master (XLR) output

• BGM (XLR) output

• Emergency signal input

• Two trigger inputs

• RS-232 (DE-9)

• Three (cinch) CD, tape, aux inputs

• Six 100 V speaker outputs

• 24 VDC output

• 24 VDC input

• Three control inputs

• Ground screw

• IEC mains socket

Certifications and approvals

Safety acc. to EN 60065

Immunity acc. to EN 55103-2

Emission acc. to EN 55103-1

Region Certification

Europe CE

Installation/configuration notes

LBB 1925/10 rear view

Parts included

Quantity Component

1 LBB 1925/10 PLENA System Pre-amplifier

1 Power cord

1 Set of 19”mounting brackets

1 Plena CD

1 Installation and User Instructions

Technical specifications

Electrical

Mains power supply

Voltage 230/115VAC, ±15%, 50/60 Hz

Current inrush 230/115 VAC, 1.5/3 A

Max power consumption 25 VA

Battery power supply

Voltage 24 VDC, +10% / -15%

Current max 1 A

Performance

Frequency response 50 Hz to 20 kHz (+1 / -3 dB)

Distortion <0.5%

Bass control ±10 dB @ 100 Hz

Treble control ±10 dB @ 10 kHz

Channel separation >70 dB @ 1 kHz

Priority mute >40 dB

Dynamic range 100 dB

Mic/line input 1 x

Connectors 5‑pin DIN, 3‑pin XLR, balanced, with

phantom power

Sensitivity 1 mV (mic), 200 mV (line)

3 | LBB 1925/10 Plena System Pre-Amplifier

Impedance >1 kohm (mic); >5 kohm (line)

S/N (flat at max volume) >63 dB (mic); >70 dB (line)

S/N (flat at min volme/muted) >75 dB

CMRR >40 dB (50 Hz – 20 kHz)

Headroom >25 dB

Speech filter -3 dB @ 315 Hz, high-pass,

6 dB/oct

Phantom power supply 16 V via 1.2 kohm, (mic mode only)

Line input 3 x

Connector Cinch, stereo converted to mono,

unbalanced

Sensitivity 200 mV

Impedance 22 kohm

S/N (flat at max volume) >70 dB

S/N (flat at min volume/

>75 dB

muted)

Headroom >25 dB

Master output 1 x

Connector 3-pin XLR, balanced

Nominal level 1 V

Impedance <100 ohm

Tape output 1 x

Connector 3-pin XLR, balanced

Nominal level 200 mV

Impedance <100 ohm

Relay contacts 30 V, 1 A

DC supply output voltage 24 V, 250 mA max

Mechanical

Dimensions (H x W x D) 100 x 430 x 270 mm

(19" wide, 2U high)

Weight Approx. 5 kg

Mounting Standalone, 19" rack

Color Charcoal

Environmental

Operating temperature -10 ºC to +55 ºC (14 ºF to +131 ºF)

Storage temperature -40 ºC to +70 ºC (-40 ºF to

+158 ºF)

Relative humidity <95%

Ordering information

LBB 1925/10 Plena System Pre-Amplifier

6-zone, 2-channel distribution system unit with call
and BGM (background music)

Order number LBB1925/10

Connector Cinch, 2 x mono

Nominal level 350 mV

Impedance <1 kohm

Headphone output 1 x

Connector 6.3 mm jack stereo, signal mono

Nominal level 3 V

Impedance <100 ohm

Zone relays 5 A

Contacts voltage 250 V

Contacts current 8 A

Interconnection input /

1 x

emergency

Connector 3-pin XLR, balanced

Sensitivity 200 mV (interconnection),

100 mV to 1 V adjustable
(emergency)

Impedance >10 kohm

VOX threshold 45 mV (emergency)

Interconnection output 1 x

4 | LBB 1925/10 Plena System Pre-Amplifier

Represented by:

Americas: Europe, Middle East, Africa: Asia-Pacific: China: America Latina:

Bosch Security Systems, Inc.
12000 Portland Avenue South
Burnsville MN 55337, USA
Phone: [phone]
Fax: [phone]
[e-mail]
www.boschsecurity.com

Bosch Security Systems B.V.
P.O. Box 80002
5617 BA Eindhoven, The Netherlands
Phone: + 31 40 2577 284
Fax: [phone]
[e-mail]
www.boschsecurity.com

Robert Bosch (SEA) Pte Ltd, Security
Systems
11 Bishan Street 21
Singapore 573943
Phone: [phone]
Fax: [phone]
[e-mail]
www.boschsecurity.asia

Bosch (Shanghai) Security Systems Ltd.
201 Building, No. 333 Fuquan Road
North IBP
Changning District, Shanghai
200335 China
Phone [phone]
Fax: [phone]
www.boschsecurity.com.cn

Robert Bosch Ltda Security Systems Division
Via Anhanguera, Km 98
CEP 13065-900
Campinas, Sao Paulo, Brazil
Phone: [phone]
Fax: [phone]
[e-mail]
www.boschsecurity.com

© Bosch Security Systems 2012 | Data subject to change without notice
1886277131 | en, V1, 23. Nov 2012